Electric water heater



Dec. 7, 1937. F. w. SCHARF Y ELECTRIC WATER HEATER Filed NOV. 29, 191'5'` 2 Sheets-Sheet l v INVENToR.

FQHNK W SCHH/QF A TTORNEY.

Dec. 7, 1937. Fpw. SCHARF 2,101,691

ELECTR IC WATER HEATER VFilm1 Nov. 29, 1955 2 sheets-sheet 2,.

IN VEN TOR.

@WMM

ATTORMEY.

Patented Dec. 7, 193':`

UNITED STATES PATENT OFFICE Application November 29, 1935, Serial N0. 52,024

13 Claims.

My invention relates to water heaters and more particularly to electric heaters for hot water tanks.

An object of my invention is to provide a relatively simple and efficient flexible electricl Other objects of my invention will either be apparent from the description of one form of device embodying my invention or will be pointed out in the course of such description.

In practicing my invention I provide a flexible band-like multiple-element electric heater adapted to be located around a hot water tank and to be clamped thereagainst, a tunnel-like casing being provided around the tank in heat-insulating material enclosing the same, said tunnel structure having an outer opening at one point. The Iiexible heater can be inserted into and removed from its operative position around the tank through the opening, which is normally closed by a cover plate supporting a thermostat and a control switch for the heater.

In the drawings,-

Figure l is a View in vertical section through a water heater assembly embodying my invention,

Fig. 2 is a horizontal lateral section therethrough taken on the line 2*2 of Fig. 1,

Fig. 3 is a View in horizontal lateral section taken on the same plane as Fig. 2, but showing an intermediate stage of assembly or disassembly of the iexible heater.

Fig. 4 is a plan view of a multiple-element electric heater embodying my invention,

Fig. 5 is a fragmentary sectional view taken on the line 5 5 of Fig. 1, and showing the means for clamping a tunnel-like structure around the tank,

- Fig. is a View in front elevation of one resistor support,

Fig. '1 is a longitudinal sectional view therethrough taken on the'line 1-1 of Fig. 6,-and

Fig. 8 is a lateral sectional view through the single element shown in Fig. 6 and taken on the line 8 8 thereof.

Referring first to Fig. 1 of the drawings, I have there illustrated a water heater assembly designated in general by the numeral il and embodying an ordinary hot water tank I3 provided with a cold water inlet I5 and a hot Water outlet I1 in a manner well known in the art. The assembly is supported on a plurality of legs 2| in a manner Well known in the art.

In order to make the assembly as efficient as possible in regard to the conservation of heat, I prefer to surround the tank I3 over substantially its entire surface with a relatively thick layer of heat-insulating material 23 in a manner now well known in the art, and to protect the same by an outer casing 25 which may be made of thin sheet metal or of any other suitable material and having a bottom closure 21 and a top cover 29 associated therewith to protect the outer surface of the heat-insulating material 23. The top cover may be heldin place by a nut or cap plug 30 screwed on a short piece of pipe tting into a part of the hot water outlet.

I provide further a plurality of tunnels 3l and 33 in the heat insulating material, which tunnels are constituted by a plurality of pieces of sheetl metal comprising a single flat arcuate piece oi' sheet metal 35 located at the top of a tunnel, a similar arcuate piece 31 located at the bottom of the tunnel, and an outer annular cover 39. The tunnel is provided with an opening 4| therein at one point in its circumference and the outer cover sheet 39 is adapted to be bent outwardly and to substantially abut the outer cover member 25 which is also provided with an opening 43 registering with the opening 4l in the tunnel. If desired, I may make the arcuate members 35 and 31 of a number of arcuate pieces whose ends overlap with each other, but this is a detail of manufacture, the object in general being to provide a substantially open tunnel around one or two peripheral points of the tank to receive a multiple element heating unit hereinafter to be described. The adjacent ends of the upper and lower arcuate walls 35 and 31 are bent laterally, as shown in Fig. 5 ofthe drawings, to provide clamping anges 44 held by one or more short machine screws as shown.

A exible band-like multiple element heater 45, shown more particularly in Fig. 4 of the drawings, comprises a plurality of refractory elongated bars 41 whose shape and contour is shown more particularly in Figs. 6 and 7 of the drawings, and Whose cross-section is shown in Fig. 8 of the drawings. As there shown, each refractory bar comprises a body portion 49 which constitutes the rear portion of the block 41 and Which has a front portion 5| which is slightly wider than the back portion 49 and which is provided with a plurality of laterally-extending recesses o-r saw cuts 53.

A resistor wire 55 is located in the lateral grooves or slots 53 and extends in zigzag fashion therein along the front part of the block 'i, the return bent portions thereof seen in Fig. 6 of the drawings being located under the laterally projecting ends of the slotted portion 5l.

Each block 51 is provided with an upper opening 5l and a lower opening 59 extending therethrough to receive therein relatively heavy current conductors 6l to permit of suitably energizlng the resistor elements which may be connected either all in series or, as shown in Fig. 4 of the drawings, may be connected in such manner that half of the resistor supporting blocks il have their resistors connected in series and the two sets are connected in parallel. This, however, is a matter of choice, depending upon the size of wire to be used and upon the available voltage of the supply circuit.

The lateral grooves 53 do not extend over the entire front surface of each block ll, but stop short of each end thereof as will be seen by reference to Figs. 6 and 7, and terminal members 63 and65 are provided at the upper and the lower ends of each block extending therethrough in order to permit of making the desired electrical connections between the individual blocks, which electrical connections are designated by numeral 6i in Fig. 4 of the drawings and may consist of an integral part of the resistor or of short pieces of copper wire, or any other suitable means for connecting the individual elements.

A exible metal band 69 is provided to which each of the resistor-supporting blocks is bolted aS by means of short machine bolts 'il (see Fig. 7 of the drawings), the band 69 being located in a laterally-extending recess l2 in each block di, the heads of these bolts being located in a. relatively deep opening 13 in the mid-portion of each block so that the head of the metallic bolt will be located a suitable distance away from the resistor 55. Electric-insulating material l@ may be located between the resistor and the bolt. The general view of the assembled multiple-element heater is shown in Fig. 4, and this heater is shown in its proper operative position in a tunnel 3| in Fig. 2 of the drawings. It will be noted that the end portions of the exible band 69 are bent laterally away from 'the adjacent portion and that a clamping bolt 'l5 is used to connect the two laterally projecting end portions of the band 69 whereby to draw it tightly around the individual blocks il causing them to closely opv eratively engage the outer surface of the tank i3.

A control box lll is located in each of the openings l and supports a thermal control element shown as including a metallic bulb or enclosure i9 adapted to extend ino the tank i3 through the w'all thereof and to be protectedby a well 80 of tubular shape having a water tight connection With the wall of the tank, whereby to provide means to control the energization of the heater 65. A knob 8l is associated with each thermal control means in order to adjust the same for dierent operating temperatures and if desired, a manual operable switch indicated by a knob 83 may be located in the structure 'l1 in order to permit of manually controlling the energization of the associated heater. The structure 'il may be supported by a front closure member B5 in the shape of an arcuate plate having its edge portions overlapping the outer cover 25 to which it may be secured by a plurality of small machine screws 81.

Referring now to Fig. 3'of the drawings, I have there illustrated the flexible band-like heater as in the process of being removed from the tunnellike casing around the tank. In order to do this all that is'necessary is to remove the front or outer closure plate 85 to disconnect from the control box il the leads 89 (see Fig. 2) extending between it and the heater and then to remove the clamping bolt l5. Itis obvious that the band-like heater and particularly the lower ends of the blocks '3l will normally rest upon the upper surface of bottom plate 3l and the openings il and i3 are made large enough so that when the plate 35, and the control box and thermostat bulb are removed, it will be easy to pull out the band-like heater d5' by grasping one end of the band 69 and pulling it outwardly substantially as shown in Fig. 3 of the drawings.

After repair of this heater, it or a, new heater unit may be inserted into its proper operative position in the tunnel-like casings by simply reversing the process of removing the same, that is, pushing one end of the heater through the aligned openings il and d3 until the irst end has been pushed around through substantially 360 when it will be easily possible to insert the clamping bolt 'l5 through the laterally bent ends of the band 69 and clamp it tightly against the tank. The other connections, such as those to the control box ll, may then be made and the device is then ready for operation.

The device embodying my invention thus provides a relatively simple assembly for a iiexible hot water heater applicable to hot water tanks, in which the heat from the electric resistor wires is applied directly against the outer surface of the tank and it is therefore possible to use a relatively low temperature heater so that deposits' tively high temperature areas applied either to.

the tank or provided inside of the tank.

The device embodying my invention provides a heater which can be very easily and quickly located in its proper operative position or removed therefrom without disturbing the rest of the tank assembly, and in which the possibly granular heat insulating material usually placed around a tank of this kind will not directly operatively engage the heater unit itself.

While I have illustrated and described a specic embodiment of my invention, I do not desire to be limited thereto and desire that the appended claims shall be so construed as to cover all similar devices operative for the same purpose and that they s'hall be limited only by the prior art.

I claim as my invention:

1. A water heater assembly for a tank, including an annular compartment around the tank having top, bottom and outside walls and an opening in the outside wall and a flexible multielement electric heater located in the compartment insertable into and removable from the compartment through said opening, and means to clamp said heater around said tank.

2. A water heater assembly for a tank having heat insulating material therearound, said assembly including a tunnel in the heat-insulating material having an outside opening therein at one point, a plurality of individual heating elements spaced around the tank, a flexible band to which the elements are secured adapted to clamp the elements against the tank and means to secure the ends of the band together to effect such clamping, the ends of the band being located at said opening in the tunnel.

3. A water heater assembly for a tank, said assembly comprising a tunnel extending around the tank having an outer opening therein and a band-like electric heating unit insertable into and removable from its operative position in said tunnel through said opening.

4. A water heater assembly lfor a tank having heat-insulating :material therearound, said assembly comprising a tunnel in the heat insulating material extending around the tank having an outer opening therein, a flexibly mounted plurality of individual heating elements insertable into and removable from their operative positions in said tunnel through said opening and means located adjacent said opening and operable therethrough to tightly clamp the heating elements against the tank.

5. A Water heater assembly for a tank having a layer of heat-insulating material therearound, said assembly including a metal casing having top, bottom and outer walls and an opening in the outer wall clamped around the tank, a flexible band-like electric heater insertable into and removable from its operative position in said casing, through said opening.

6. A water heater assembly for a tank having a layer of heat-insulating material therearound, said assembly comprising a tunnel in the heatinsulating material having an outside opening, a plurality of electric heating elements in the tunnel, spaced peripherally around the tank, a iiexible strip located on the outside of the elements having its ends located at the opening in the tunnel and means operable through the opening to eifect tight clamping engagement of the heating elements against the outer surface of the tank by thel flexible strip.

7. A water heater assembly for a tank having a layer of heat-insulation therearound, said assembly comprising a flexible band-like multi-element electric heater encircling the tank and adapted to be tightly clamped therearound, and means for effecting removal of a damaged heater and insertion of anew heater without aiecting said heat insulation, said means comprising an annular chamber having atop, a bottom and an outside wall with an opening in the outside wall and means to clamp the chamber around the tank.

8. Awater heater assembly for a tank having a layer of heat insulating material therearound Aand an outer cover for the heat insulating material and having an opening therein, said as-` located in said casing. insertable into and removable from its proper operative position through said alined openings in the casing and in the cover, a thermostatic control means for the heater operatively engaging the tank and a closure plate for'the openings secured to the outer cover and supporting the thermostatio control means.

, 9. A Water heater assembly fora tank, comprising a heat-insulated compartment extending around the tank and having a top, a bottom and `an outer Wall'with an opening in said outer wall, a flexible electric heater located in said compartment and adapted to be removed therefrom through said opening and means operable.

through said opening to clamp the heater in tank-engaging position.

10. A device as set forth in claim 9 and including a cover member for the opening in said outer wall and a control box for the heater supported by the cover member.

1l. A water heater adapted to be mounted on a hot water tank and comprising a plurality of refractory resistor-supporting bars, resistor wires supported by said bars adjacent to one face of the respective bars, a iiexible clamping band adjacent to the other face of the respective bars, means securing each bar to the band, electric energizing conductors extending through certain of said bars and means to draw the ends of said band toward each other to clamp the bars against a tank.

12. A water heater adapted to be mounted on a hot water tank, comprising a plurality of refractory resistor-supporting,bars, resistor Wires supported by said bars adjacent to the inner faces thereof, a flexible clamping band located against the outer faces of the respective bars and having intertting engagement therewith, bolts extending through therespective bars and the band to hold them in proper relative operative positions, energizing conductors supported by and extending through certain of the bars adjacent the ends thereof and means to draw the ends of the band toward each other to clamp the heater against a tank.

13. A water heater assembly for a tank including a compartment located against theouter surface of the tank and comprising top, bottom and outside walls and an opening in the outside wall and a flexible electric heater in the compartment insertable into and removable from lthe compartment through said opening," said heater including a plurality of electric-insulating bars,

resistor wires supported by said bars adjacent the 5 inner faces thereof, a flexible band having interfitting engagement with the respective bars at the tol outer faces thereof, bolts holding the respective bars against 'the band, energizing conductors extending'through certain of the bars adjacent to the ends thereof and means to draw the ends of the band toward each other to clamp the bars against the tank. FRANK W. SCHARF. 

